Had an HP 4L, loved it. Just printed almost ad nauseum for very little cost. (One owner-user’s review on the web called it the “Energizer Bunny of printers”) and -- from my experience, at least, I tend to agree.)
So ... what printer can I get today -- new or used -- fits the same bill. Cartridge cost (or whatever you call it for whatever type of printer) and reliability are the primary concerns: e.g., ability to print in color would be nice but is not critical. Probably print a ream or two of paper per month.
Stay away from "consumer" models HP printers. A 2000 series used will work well, I have worked with many 2100, 2200 models, don't think I have seen any fail. 4000 series are great also. This is from experience working in tax offices where they print thousands of pages weekly.
only get a used printer if you know what your looking at. If it has stuffed pickup rollers and stuffed fuser you will be up for $$$$ to repair it......... I have the opposite opinion, get a cheap consumer Laser printer from HP/canon/lexmark, but get the extended warranty for 3 years. Laser printers are expensive to repair, just get something cheap and throw it away when its failed.